Existing internal combustion devices promote engine shut-down in the event of a failure in engine oil pressure, as shown in U.S. Pat. No. 4,080,946. The engine shut-down function results in a complete shut-down which requires a repriming of the fuel system before the vehicle can be moved by its own power. Additionally, such engine shut-down systems require valves, switches, gauges, relays and coils. These component ports are subject to corrosion and malfunction which results in a inoperative system. The inventor's prior invention provided an engine protection system that will allow the engine to idle allowing the operator to move the vehicle out of traffic patterns. The present invention provides a fluid or air pressure activated cylinder in series with the engine throttle rod to mechanically vary the length of the engine throttle rod or cable to limit the Available engine speed. The prior system did not allow quick response at one pressure to provide air or oil pressure and a quick shut down to idle at a shift pressure close to said one pressure. The present improvement invention provide an improved control system.